The invention relates to a compensating shaft for reciprocating piston engines with at least one compensating weight with an eccentric center of gravity, the compensating weight being connected torsionally elastically to the compensating shaft. In modern internal combustion engines, compensating shafts are used to reduce vibrations and running noises. However, their effect and success is satisfactory only when the compensating shaft unit itself also runs in a quiet and vibration-free way.
Vibrations of the compensating shaft unit can be excited by the moving masses of the engine and by its rotational irregularity. The latter are, on account of the clearances in their drive and the small torque transmitted via it, a noise source which is particularly difficult to control; moreover, great load with a changing sign is exerted on the teeth by virtue of the rotational irregularity. Minimizing the tooth clearances is problematic on account of the temperature differences arising and increases manufacturing costs enormously.
It is known to provide the driving toothed wheel on the crankshaft of the engine with an elastic connection between the toothed ring and the wheel body, for instance from U.S. Pat. No. 3,667,317, but this isolation from excitation by the crankshaft allows the masses of the entire compensating shaft unit the freedom to vibrate.
It is furthermore known from JP 2000-283238 AA to provide a torsionally elastic connection between a compensating weight and a bushing made as a hollow shaft. This connection consists of rubber, which is fitted between claws in the interior of the compensating weight and external claws of the bushing.
It is therefore an object of the invention to achieve effective noise reduction in a compensating shaft unit by torsionally elastic connection to the compensating shaft with minimum manufacturing costs (simple assembly included).